Fibromatosis of infancy and childhood. Histology, ultrastructure and clinicopathologic correlation.

Fifty-nine cases of fibromatosis in children were investigated. To our knowledge, this is the largest serie with clinicopathologic datas reported so far in German literature. The most frequent type was infantile (desmoid-type) fibromatosis. More than 50% of the tumours developed in the first five years of life. The overall male-to-female ratio was 1.36:1. The lower extremities were the most frequent site of manifestation. Vimentin could be demonstrated in the tumour cells by immunohistochemical methods. Positive staining for dipeptidylaminopeptidase (DAP) IV suggested a myofibroblastic nature of some of the neoplastic cells. These results were supported by ultrastructural examination. Two cases demonstrated the unpredictable biological behaviour of fibromatosis. It is emphasized that clinical behaviour depends on number, size, location and histologic appearance of the lesions as well as age of the patient.